首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   143篇
  免费   8篇
  国内免费   1篇
化学   99篇
晶体学   1篇
力学   5篇
数学   15篇
物理学   32篇
  2023年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   7篇
  2015年   5篇
  2014年   2篇
  2013年   9篇
  2012年   11篇
  2011年   7篇
  2010年   11篇
  2009年   4篇
  2008年   6篇
  2007年   6篇
  2006年   10篇
  2005年   5篇
  2003年   3篇
  2002年   6篇
  2001年   2篇
  2000年   5篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1984年   9篇
  1982年   6篇
  1980年   1篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
  1969年   1篇
  1968年   2篇
  1967年   1篇
  1946年   1篇
排序方式: 共有152条查询结果,搜索用时 15 毫秒
51.
Journal of Solid State Electrochemistry - Electrodeposited Cu2O coatings with 111 out-of-plane orientation were found to have the lowest reversible discharge capacity as anodes for Li-ion cells....  相似文献   
52.
53.
Kamath VA  Parekh PP 《Talanta》1969,16(3):345-350
A simple and rapid method has been developed for the determination of isotopic radium, based on gamma-ray spectrometry. (228)Ra and (224)Ra are assayed by measuring the intensities of the photo-peaks in the 0.94 and the 2.62 MeV regions of the gamma-spectrum. The interference in these measurements, arising from the presence of the (226)Ra(210)Pb chain in the sample, is obviated by the almost complete expulsion of (222)Rn from the system. The precision of the method is +/-2% and +/-3 % in the determination of (228)Ra and (224)Ra respectively, the absolute sensitivities being 2 and 0.5 nCi. The method has been applied to evaluate the distribution of these isotopes in the various products of the Indian Rare-Earths Factory, Alwaye.  相似文献   
54.
Results of investigations on the adsorption of CO andO 2 on transition metal surfaces by employinguv and x-ray photoelectron spectroscopy and electron energy loss spectroscopy (eels) are presented. Results of molecular orbital calculations on adsorbed CO and O2 are also discussed. Some of the interesting aspects discussed are, satellites in the O(ls) region due to adsorbed CO, vibrationaleels of adsorbed O2 and dissociation energy profiles of adsorbed O2 on clean surfaces as well as surfaces covered with potassium or presorbed atomic oxygen. Contribution No 245 from the Solid State and Structural Chemistry Unit.  相似文献   
55.
Cure characteristics of hydroxyl terminated polybutadiene (HTPB) prepolymer with avariety of blocked toluene diisocyanate (TDI) in the presence of triethylamine (TEA) andchloroacetic acid catalyst are reported. Phenol, thiophenol, p-chloropheno1, p-nitrophenol,p-cresol, resorcinol, naphthols, caprolactam and butylated-hydroxytoluene were used as blockingagents. Viscosity measurements have been carried out using a mixture of HTPB and blocked TDIin cyclohexanone in the presence of the catalysts at 50℃ and 60℃ using Haake rotational vis-cometer. Viscosity measurements have also been carried out with 50% solids such as ammonium sulphate along with HTPB and TDI adduct.  相似文献   
56.
Let G be a graph and v be any vertex of G. Then the neighborhood contracted graphGv of G, with respect to the vertex v, is the graph with vertex set V ? N(v), where two vertices u,wV ? N(v) are adjacent in Gv if either w = v and u is adjacent to any vertex of N(v) in G or u,w ? N[v] and u,w are adjacent in G. The properties of the neighborhood contracted graphs are discussed in this paper. The neighborhood contraction in some special class of graphs, the domination in a graph and the neighborhood contracted graphs are discussed in the paper.  相似文献   
57.
Individuals with diabetic foot ulcers have overlapped the inflammatory, proliferative and remodeling phase, making the tissue vulnerable to delayed healing responses. We aimed to establish the dose–response relationship of photobiomodulation therapy of different doses and matrix metalloproteinases in the healing dynamics of diabetic neuropathic ulcers. Diabetes was induced in 126 Albino Wistar rats, and neuropathy was induced to the hind paw by a sciatic nerve injury method. An excisional wound was created on the neuropathy-induced leg. Photobiomodulation therapy of dosages 4, 6, 8, 10, 12 and 15 J cm−2 and wavelength 655 nm and 808 nm was irradiated. Photobiomodulation therapy of dosages 4, 6 and 8 J cm−2 showed better wound healing properties with optimized levels of matrix metalloproteinases-1 and 8. We observed a strong dose response in the experimental group treated with 6 and 8 J cm−2. The findings from the present study conclude that photobiomodulation therapy of dosages 4, 6 and 8 J cm−2 is suggestive of usefulness in diabetic neuropathic ulcer healing. Markers like matrix metalloproteinases may give a clear direction on response to the therapy. Based on the findings from the present study, we recommend to validate the findings for safety and efficacy in future through human prospective randomized controlled clinical trials.  相似文献   
58.
Iyer CS  Kamath VA 《Talanta》1980,27(6):537-540
The determination of niobium at levels of 0.01% and below is required in certain specifications for stainless-steel welding electrodes, containing 2-3% molybdenum and 0.01% titanium. A method has been developed, based on initial extraction of niobium thiocyanate into butyl acetate followed by stripping with fluoride and re-extraction of niobium thiocyanate after masking of the fluoride by addition of boric acid. The absorbance of the extract is measured at 385 nm. Mo, Ti, V and W can be tolerated at 50 times the concentration of Nb. For higher amounts of Mo, corrections can also be applied. Ta should, however, be restricted to ten times the Nb level. Precision and accuracy of the method are satisfactory. The time taken for an individual determination is about an hour. The method is applicable to mild, low-alloy, stainless and niobium-stabilized steels.  相似文献   
59.
60.
Activation energy for the curing process of epoxy glass mica tape has been experimentally determined from differential scanning calorimetric measurements and found to be 20 kcal/ mol. Thermochemical calculation shows that the rate controlling step is the dissociation of the C-O bond in the epoxide leading to ring opening and its subsequent reaction with amine hardener. Shelf life has been determined from the measurement of the enthalpy loss corresponding to the curing during the aging process. The kinetics of the aging process also yields an activation energy of 20 kcal/mol which corresponds to the slow curing of the epoxy resin.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号